(A) Field of the Invention
This invention relates to a test sample color comparison device used in biochemical examinations (urine sugar, blood sugar, urobilin and other such examinations), for example, the invention relates to a test sample color comparison device used to determine the amount of sugar present in urine by comparing the color of portion of a test paper treated with a reagent and wetted by urine with a plurality of reference color shades representing different levels of urine sugar.
(B) Brief Discussion of the Prior Art
FIG. 5 illustrates a prior art test sample color comparison device. It is constructed of a cylindrical case 62, equipped with a cap section 61, on which a color sample sheet 63 used for a color comparison is attached. The cylindrical case contains, for example, test sticks 64 used in urine sugar examinations. Test stick 64 is a resin sheet having a test paper 65 which has been soaked in a reagent attached to one end. When conducting a urine sugar examination, cap 61 is removed, a test stick 64 is removed from the cylindrical case, and test paper 65 is wetted with urine. The urine wetted test stick 65 displays various color reactions in response to the sugar level in the urine. The resultant color appearing on test paper 65 is compared with the color sample 63 provided for comparative purposes on cylindrical case 62 to determine a color which best matches the color of test paper 65 thereby giving an indication of the urine sugar level. That is, the various colors 63a (colors indicating positive and negative sugar results) which result according the level of sugar in the urine (glucose) are arrayed on color sample sheet 63. By comparing the color of the test sample paper 65 with the various colors 63a on the color sample sheet a determination of the level of sugar in the urine can be made by finding the same or approximately the same color.
Because the color sample sheet 63 is attached to the outside of the cylindrical case 62 which holds the test sticks, the test paper 65 wetted with urine must be held close to the color samples 63a for comparison with each. In other words, during the process of color comparison, it is necessary for one to hold the urine wetted test paper so that it does not come in contact with the color samples, but yet move the test sample from color to color. This requires special diligence and dexterity on the part of the person making the comparison, making it easy to misalign the test sample paper with the color sample to be compared, and having the disadvantage that it is difficult to accurately determine slight color differences.
In an effort to solve this problem the inventors have developed the color comparison device shown in FIG. 6, which does not require one to hold the test stick. This device comprises a rotating color sample plate 73 which supports a sample color sheet 73a having multiple color shades positioned circularly about the plate and which is fitted onto a shaft 72 of a fixed circular plate 71 through a rotating plate 74, and a slot section 75 formed on the fixed circular plate 71 for receiving and positioning the color test paper for comparison with the various color shades on sample color sheet 73a.
Slot section 75 is secured at a base end 75a and the other forward end 75b is a free end in relation to the rotational orbit of the rotating plate 74 which fits around the accepting shaft 72. Free end 75b is configured and arranged as an up-down spring which is pushed down by protruding cogs 76 located around the circumference of rotating plate 74.
In between the plurality of adjacent protruding cogs 76 which are used for pushing down the free end 75a of slot section 75 are open sections 78 which are shaped to correspond with window openings 77 of rotating color sample plate 73, and which allow an operator to view a color test paper held on slot section 75 through an aligned open section 78 and a window opening 77.
To make a color comparison using this color comparison device, a test stick is placed in the slot 75c of slot section 75, and the forward colored end of the color test paper is viewed through an aligned open section 78 and window 77. The rotating plate 74 is then rotated until a color shade on the color sheet 73a which best matches the color of the color test paper is positioned adjacent a window 77 through which the color test paper is viewable. During rotation of plate 74, as shown in FIG. 7, a protruding cog 76 applies a downward force to push slot section 75 down. Further, during rotation of plate 74, after the protruding cog 76 engages with and pushes down on slot section 75, it leaves slot section 75 allowing it to return upwardly by its own resilient bias. At this time, slot section 75 is freed from the downward pressure of the protruding cog 76 and it moves upwardly and between cogs 76. This brings a test paper in slot 75c, through rotation, into view through an open section 78 and an aligned window 77. By continuing to rotate the plate 74 in this manner, the color of a color test sample can be successively aligned with the various color shades 73a arrayed in a circular pattern in between windows 77 and compared therewith to determine the same or approximately the same color.
With this type of color comparison device, because a color comparison can be conducted by holding the test stick secure and by rotating the comparative color sample section 73, the color comparison process can be conducted easier and more quickly than with the FIG. 6 comparison device. However, because the FIG. 7 color comparison device produces severe up-down motion of the slot section 75, not only does the support point 75a of the slot have a low reliability, but the up-down drive section requires that the outer shape of the comparison device be relatively large which is disadvantageous.
Thus, an object of this invention is to provide a more reliable test sample color comparison device that can be made smaller and which allows a color comparison operation to be easily and quickly conducted.